Compilare: user.cpp: In function ‘void BFS(int, int)’: user.cpp:22:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0;j < G[u].size();++j) ^ user.cpp: In function ‘int main()’: user.cpp:41:21: warning: unused variable ‘cc’ [-Wunused-variable] int n, m, u, v, cc = 0, s; ^ user.cpp:39:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.in", "r", stdin); ^ user.cpp:40:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.out", "w", stdout); ^ user.cpp:43:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &s); ^ user.cpp:46:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &u, &v); ^